An oil and gas facility run by Mexican state firm firm Petroleos Mexicanos (Pemex) was evacuated on Sunday after a fire broke out broke out according to reports. Early reports have suggested that five people have been and many more have been injured, with an operation in place to search for missing workers.

The blaze took place at the E-Ku-A2 platform at the Ku-Maloob-Zaap oil field in the Bay of Campeche but was brought under control around 4.30 p.m. (2130 GMT), according to a statement released by Pemex. The company also confirmed that the fire caused them to cut about a quarter of Mexico’s oil production, with the platform still out of operation.

The injured were being treated for burns in hospitals, and the cause of the fire at the E-Ku-A2 platform would be investigated, according to Pemex Chief Executive Octavio Romero told a news conference.

Although the cause of the fire is so far unknown, it broke out as workers were carrying out maintenance work on the platform.